1. Technical Field
The present invention relates generally to apparatus and systems for transmitting and sending electromagnetic radiation. More particularly, the apparatus and systems relate to transmitting and sending electromagnetic radiation with antennas. Specifically, the apparatus and systems of the present invention involve a tapered slot antenna for transmitting and sending electromagnetic signals.
2. Background Information
Tapered slot antennas (TSAs) belong to the general class of end-fire travelling wave antennas and include a tapered slot etched onto a thin film of metal. A TSA can be very economically etched onto a printed circuit board (PCB) film with or without a dielectric substrate on one side of the film. TSAs can be formed on PCBs of mobile devices such as cellular telephones. Besides being efficient and lightweight, TSAs are often used because they can work over a large frequency bandwidth and produce a symmetrical end-fire beam with appreciable gain and low side lobes. TSAs also generally have wider bandwidth, higher directivity and are able to produce more symmetrical radiation patterns than other antennas such as horn antennas.
TSAs are a class of endfire antennas known as surface wave antennas. Several types of TSAs exist, the most common being linear-tapered slot antennas (LTSAs), Vivaldi-tapered slot antennas (VTSAs) and constant-width tapered slot antennas (CWTAs). The beam widths of CWSAs are typically the smallest, followed by LTSAs and VTSAs. The side lobe levels are typically the largest for VTSAs, followed by LTSAs and CWSAs.
A TSA is formed by slowly increasing the width of a slot from the point of its feed to an open end of width generally greater than λO/2, where λO is the center frequency. The impedance, bandwidth and radiation patterns of the TSA are greatly affected by parameters such as length, width and taper profile of the TSA. The dielectric substrate's thickness and relative permittivity can also contribute to the efficiency of the antenna. While current TSA's provide good performance characteristics at relatively inexpensive costs, improvements can be made.